Chapter 14: Nervous Tissue SYDNEY Flashcards
what is the nervous system?
the body’s primary communication and control system
functions of the nervous system
-monitor changes: inside and outside, sensory input
-process and interpret
-causes a response: motor output, effector organs
for convenient organizational purposes, what two categories is the nervous system divided into?
-structural
-functional
types of structural nervous systems
-central nervous system (CNS)
-peripheral nervous system (PNS)
types of functional nervous systems
-sensory nervous system
-motor nervous system
what parts of the body are included in the CNS?
-brain
-spinal cord
how is the brain protected in the CNS?
protected and enclosed within the skull
how is the spinal cord protected in the CNS?
housed and protected within the vertebral canal
what are the two types of nerves that are included in the PNS?
-cranial nerves: 12 (nerves that extend from the brain)
-spinal nerves (nerves that extend from the spinal cord)
-ganglia
what is ganglia
clusters of neuron cell bodies located outside the CNS
the sensory motor system and motor nervous system both perform three general functions:
-collect information
-process and evaluate information
-initiate response to information
what happens when information is collected?
specialized PNS structures called receptors detect changes in the internal or external environment (stimuli) and pass them on to the CNS as sensory input
what happens during process and evaluating information?
after processing sensory input, the CNS determines what, if any, response is required
what happens during the initiating response to information?
the CNS initiates specific nerve impulses called motor motor output. motor output travels through structures of the PNS to effectors
the sensory nervous system is subdivided into:
-somatic sensory
-visceral sensory
function of somatic sensory system
sensory input that is voluntarily perceived from receptors
what are the somatic sensory components?
general somatic senses: touch, pain, pressure, vibration, temperature, and proprioception (sensing position or movement of joints and limbs)
special senses: taste, vision, hearing, balance, smell
function of visceral sensory system
sensory input that is involuntarily perceived from receptors of blood vessels and internal organs
what are the visceral components?
components transmit nerve impulses from chemical compostion of blood to the CNS
types of neurons in the sensory nervous system
afferent neurons
what does the term afferent mean?
-inflowing
-indicating that nerve impulses are transmitted to the CNS
types of neurons in the motor nervous system
efferent neurons
what does the term efferent mean?
-conducting outward
-indicating that nerve impulses are transmitted from the CNS
what is the sensory nervous system responsible for?
receiving sensory information from receptors and transmitting this information to the CNS
what is the motor nervous system responsible for?
transmitting motor impulses from the CNS to effectors (muscles or glands)
the motor nervous system is subdivided into:
-somatic nervous system (SNS): voluntary
-autonomic nervous system (ANS): involuntary
function of somatic nervous system
motor output that is voluntarily controlled; effector is skeletal muscle
function of autonomic nervous system
motor output that is involuntarily controlled; effectors are cardiac muscle, smooth muscle, and glands
components of autonomic nervous system
sympathetic and parasympathetic components
basic structural unit of the nervous system
neuron
functions of the neuron
-excitable cell
-long-lived
-high metabolic rate
-regeneration: unable to divide
what does the excitable cell mean?
generate, send, and receive nerve impulses
characteristic of the high metabolic rate
neurons survival depends upon continuous and abundant supplies of oxygen & glucose
structure of a neuron
-soma: cell body
-dendrites: processes that branch off the cell body
-axon: process extending from the cell body to make contact with other neurons, muscle cells or gland cells